mas, lean? Please help
 

I have a 1996 e320, the car has an idle surge problem and when running it seems to me it has a lean smell comming from the exhaust. I say lean because I have an 87 Monte SS that has to run rich and the smells are not at all alike. I cleaned the MAS with the crc cleaner to see if that would stop the surging idle but no go. The smell almost smells like some sort of chemical cleaner. Am I crazy? Also when I bring the rpm's up the car will run for a minute or 2 then stall. Any Ideas? Please help this is driving me crazy.
Karl